Laser resectoscope with ultransonic imaging means

ABSTRACT

A resectoscope for prostate surgery is provided which includes a rotating cutting element mounted within an outer sheath adapted to be inserted into the urethra. The cutting element has helical threads along the length thereof and a cutting blade at its distal end. The outer sheath has a covered distal end portion which extends beyond and over the cutting blade and has an opening therethrough adjacent the cutting blade. Within the outer sheath is an inner sheath surrounding the cutting element except for the cutting blade. A fiber optic laser filament connected to a laser generator is positioned within the space between the inner and outer sheaths and extends along the length of the inner sheath to a position adjacent the cutting blade. The optic filament is surrounded by a third sheath and is adapted to be moved by the rotation of the cutting element so that the laser light beam from the optic filament advances through tissue to cut and coagulate the resected area before the cutting blade of the cutting element reaches the resected tissue. Irrigation fluid is provided to the area between the inner and outer sheaths and is withdrawn through the inner sheath. A telescope is also provided through the cutting element for viewing the area being resected. The invention further provides for the use of ultrasound in conjunction with the laser resectoscope to plot the area of the prostate to be removed and with the assistance of a computer to control the operation of the laser to prevent cutting of tissue beyond the area of tissues to be removed.

This application is a continuation application of application Ser. No.540,072, filed Jun. 19, 1990 now U.S. Pat. No. 5,061,266 which is adivisional application of application Ser. No. 07/175,014 filed Mar. 30,1988, now U.S. Pat. No. 4,955,882.

BACKGROUND ART

This invention relates generally to the field of surgical devices, andmore specifically to a resectoscope.

A resectoscope is employed transurethrally to perform prostate and/orbladder surgery. This device has an elongate central working sectionprovided with an outer sheath, usually made of stainless steel, which isinserted into the urethra. The outer sheath prevents the urethra fromcollapsing, while the working elements internally of the sheath areemployed to cut away the desired tissue.

Conventional resectoscopes either are of the cold punch type, whereinthe cutting element is unheated, or are of the heated type, where acutting element, in the form of a conductive wire, is heated through anelectrical connection to a diathermy unit. The diathermy unit can becontrolled by the surgeon, either through the use of a hand-operatedswitch or through the use of a foot-operated switch.

In a manually operated resectoscope of the type employing a heatedcutting element, the surgeon manually extends the cutting element beyondthe end of the outer sheath to a position engaging the tissue to be cut.Thereafter, the cutting element is energized through actuation of thediathermy unit, and at the same time the cutting element is manuallyretracted to cause it to slice away a desired amount of the tissue. Thesurgeon views the area being operated upon through a telescopic systemthat also is mounted within the stainless steel sheath of the device,and a continuous irrigation system is utilized to keep the line-of-sightfree of blood and other debris.

During prostate surgery it is common to cut away approximately 1/10 of agram of tissue with each cutting stroke of the resectoscope. Althoughthe total weight of tissue to be removed varies with the size of theindividual and the severity of the problem, it is quite common to removeanywhere from 20 to 150 grams of tissue in a typical prostate operation.Therefore, in even the simplest of operations, it is generally necessaryto reciprocate the cutting element at least 200 times.

During transurethral resection of the prostate, fluids are used toirrigate during the operation as well as during the immediatepostoperative period. The fluid irrigation during the resection has twopurposes: to first clarify the area so that the operator's vision isunobstructed and second to remove any prostatic chips toward thebladder. Therefore, the bladder acts as a temporary reservoir forprostatic chips and blood clots. Before the procedure is completed, andsometimes in the middle of the procedure, the bladder must be irrigatedand cleared completely of any prostatic chips or clots. It would,however, facilitate the operation if irrigation fluid and the prostaticchips or clots could be removed without having to irrigate the bladder.

In the diathermy unit previously discussed, electricity is used both forcutting and coagulation. The electricity runs through a hot metal were(isolated in the proximal part) to cut pieces or chips of the prostateand to coagulate any bleeding areas. The use of these electricallyoperated resectoscopes has certain disadvantages. For example, there isa need for a very powerful diathermy machine; the electric loops throughwhich the electricity runs have an average useful life of only one ortwo patients; each loop costs approximately fifty dollars; and theprocedure produces tissue charring or carbonization which produces aslightly higher risk of a location for infection. (Charred tissued isdead tissue and with urine and blood flows close thereto, bacteria mightfind a suitable place to multiply.)

Furthermore, while operating time depends greatly on the size of theprostate as well as the skill of the operator, other considerations alsoincrease operating time. These include excessive bleeding and a smallbladder capacity to receive the irrigation fluid and the removal ofprostatic chips. The average skilled operator or surgeon may takeapproximately one minuite to remove each gram of prostatic tissue. Sincethe majority of prostate surgical removals are under 100 grams, e.g.,approximately 20 to 60 grams, it can be seen that the process can becomequite time consuming--and there are some prostates that range in sizefrom 100 to 250 grams. Accordingly, it can be seen that any process orapparatus which might decrease the operating time would be verybeneficial.

It is known that lasers can be very useful in surgical applications, butthere has never been an acceptable application of laser surgeryapparatus or techniques to prostate resections. Since precision cuttingand the ability to control the laser beam to control bleeding are twomajor benefits of the use of lasers in surgery, and since these are twoof the most important considerations during prostate resections, itwould be very beneficial if an apparatus were available which providesthe benefits of laser technology for prostate surgery.

A further consideration of prostate surgery is the fact that the capsuleof the prostate contains many veins, and if any of these are breached,the capsule will bleed profusively and will allow the irrigation fluidto escape outside the urinary system into the area surrounding theprostate. This not only causes pain, but electrolyte disturbance with anincreased morbidity and even possibly mortality. In order to avoidpiercing the capsule, many resectionists stop short of the capsule by0.5-1 mms or more depending on the skill of the operator and anatomy ofthe prostate. It would, of course, be benefical to get as close to thecapsule as possible in removing the prostate tissue, but it takes ahighly skilled resectionist to come this close without invading thecapsule. Such skill is only obtained after many years of practice.

In this regard, it would be very helpful if a method could be providedwhereby surgeons could perform prostate surgery knowing when they aregetting close to the capsule. Having such knowledge of the progressduring the resectioning would allow much more thorough removal of theundesireable tissue and at the same time reduce the anxieties associatedwith possible invasion of the capsule.

OBJECTS OF THE INVENTION

It is an object of this invention to increase the speed and efficiencyand decrease the cost of the cutting operation associated withtransurethral surgery of the prostate gland and/or bladder and providefor a safer operation.

It is a further object of this invention to provide a resectoscope whichprovides irrigation fluid directly to the situs of the cutting and atthe same time withdraws the irrigation fluid and the chips removed fromthe prostate through the resectoscope without the need to irrigate thebladder.

It is another object of this invention to provide a laser for use inconjunction with prostate or bladder surgery in order to enhance theaccuracy and speed of cutting and also to coagulate tissue in order tostop or minimize bleeding.

It is yet another object of the invention to provide a rotatable cuttingmember which can be automatically or manually operated for prostateresections.

It is also an object of the invention to provide an apparatus and methodwherein a resectoscope utilizing a laser as a cutting member has thelaser controlled by a computer operated in conjunction with ultrasoundin order to prevent unintentional cutting of the prostate beyond thecentral zone where the transurethral resectioning is to occur.

SUMMARY OF THE INVENTION

The above and other objects of the invention are achieved by providing aresectoscope having a rotating cutting element mounted within an outersheath adapted to be inserted in to the urethra. The cutting element hashelical threads along the length thereof and a cutting blade at thedistal end. The outer sheath has a covered distal end portion whichextends beyond and over the cutting blade and has an openingtherethrough adjacent the cutting blade. Spaced from and within theouter sheath is an inner sheath surrounding the cutting element. Theinner sheath has a length less than the cutting element so that thecutting blade at the end of the cutting element is exposed within theouter sheath. An optic fiber for transmission of a laser light (e.g.,N.D. YAG laser) or a metal conduit for transmission of the laser light(e.g., a C02 laser) is positioned within the space between the inner andouter sheaths and extends along the length of the inner sheath to aposition adjacent the cutting blade. The optic fiber or metal conduit isadapted to be moved by the rotation of the cutting element so that thelaser light beam advances through tissue to cut and coagulate theresected area before the cutting blade of the cutting element reachesthe resected tissue.

The space between the inner and outer sheaths is adapted to receiveirrigation fluid at the proximal end of the outer sheath so that theirrigation fluid flows toward the distal end of the sheaths to thelocation of the cutting blade in order to irrigate the resected area.The irrigation fluid is withdrawn through the inner sheath by a vacuumcommunicating with the inner sheath and also by the influence of thehelical threading surrounding the cutting element which directs theirrigation fluid and chips of the resected tissue rearward through theinner sheath to an outlet at the proximal end of the inner sheath.

A telescope is provided through the cutting element for viewing the areabeing resected, and automatic and manual drive mechanisms are connectedto the cutting element to provide continuous or selective rotation ofthe cutting element.

Additionally, a computer is provided so that a computer generated imageof the prostate can be prepared by means of ultrasound, for example byinserting ultrasound probes into the rectum of the patient adjacent theprostate or by using exterior abdominal probe. This computer generatedimage is used to plot the area of the prostate to be resected, and byconnecting the computer to the laser and to an ultrasound probe, thecutting of the prostate tissue can be followed by the ultrasound probeand this information fed into the computer. By comparing the location ofthe resectoscope to the original ultrasound plot of the prostate, thecutting can be contained within limited areas by having the computershut off the laser when comparison indicates that the wrong areas areabout to be cut.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and many of the attendant advantages of this inventionwill be readily appreciated as the same become better understood byreference to the following detailed description when considered inconjunction with the accompanying drawings, wherein:

FIG. 1 is a side view of the resectoscope of the present invention;

FIG. 2A is an enlarged, partial section view of the drive mechanism andproximal end of the resectoscope of the present invention;

FIG. 2B is an enlarged, partial section view of the distal end of theresectoscope of the present invention;

FIG. 3 is a section view taken along the line 3--3 of FIG. 2A;

FIG. 4 is an enlarged section view taken along the line 4--4 of FIG. 2B;

FIG. 5 is an enlarged section veiw taken along the line 5--5 of FIG. 2B;

FIG. 6 is a transverse section of the prostate; and

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

Referring in greater detail to the various figures of the drawingswherein like reference characters refer to like parts, a resectoscope ofthe present invention is generally shown at 10 in FIG. 1.

The resectoscope 10 includes a tubular outer sheath 100 adapted to beinserted into the urethra for the purpose of performing either prostateor bladder surgery, as is well known in the art. Specifically the outersheath is inserted into the urethra to prevent it from collapsing whilethe operating procedure is carried out utilizing the working elementshoused within the sheath 100.

As shown in FIG. 2B, within and spaced from the outer sheath 100 is asecond or inner tubular sheath 200, housing therein a cutting element300. The cutting element 300 is adapted to rotate within the innersheath 200. In the space between the outer sheath 100 and the innersheath 200 is a third sheath 402. This third sheath 402 is part of thelaser member 400 of the resectoscope and houses therein an optic fiberfilament 408 which transmits the laser light beam. This third sheath 402is affixed (for example, by being welded) at one end to the inner sheath200, and its free end is radially moveable within the space between theinner and outer sheaths when it is contacted by the cutting element 300.

The cutting element 300 has a longitudinal opening 302 along thelongitudinal axis thereof through which fits a telescope 500 for use inviewing the area of the bladder or prostate being resected.

The cutting element 300 is connected to a drive mechanism 600 which mayrotate the cutting element either continuously or intermittently. Aswill be described in more detail, the drive mechanism 600 is preferablypneumatically operated for continuous rotation of the cutting element300 or manually operable for more careful rotation of the cuttingelement 300.

As shown in FIGS. 1 and 2A, the outer sheath 100 includes a hollow,preferably stainless steel, first tube 101 approximately eleven incheslong. A conduit 102, which is designed for connection to a source ofsterile irrigation fluid, is provided to introduce irrigation fluid intothe resectoscope and ultimately to the area of the prostate beingresected. A valve 104 in conduit 102 controls the flow of fluid into thefirst tube 101.

The distal end of the first tube 101 has a closed end or rounded hood106 and an opening 108 on the underneath side of the tube 101. It isthrough this opening 108 that the cutting element 300 is exposed and isable to cut away at the tissue being removed. At the proximal end of thetube 101 opposite the hood 106 is a handle 110 perpendicular to the tube101 which is used to manipulate or maneuver the resectoscope 10.

The inner sheath 200, as shown in FIGS. 2A and 2B, is a hollowopen-ended second tube 202 narrower in outside diameter than the insidediameter of the first tube 101 and positioned within and longitudinallyaxially concentric with the first tube 101. A second conduit 203 isconnected to the second tube 202 and passes through the first tube 101.This conduit 203 is designed to be connected to a vacuum source (notshown) and has a control valve 206 (FIG. 1) associated therewith forcontrolling fluid flow out of the interior of the second tube 202. Thelocation where the second conduit 203 passes through the first tube 101is sealed so there is no possibility of leakage.

Within the second tube 202 is the rotatable cutting element 300. Asshown in FIGS. 2B and 5, the cutting element includes a hollow tube 304surrounded by a continuous helix or threads 306 about the circumferencethereof. These threads 306 run from the distal end of the hollow tube304 along the length thereof, but stop short of conduit 203 connected tothe vacuum source through which the irrigation fluid and removed tissueare withdrawn from the resectoscope. The longitudinal axis of the hollowtube 304 is coaxially aligned with the first and second tubes, 101 and202. At the distal end of the hollow tube 304 is a curved blade 306 forcutting and removing the desired tissue. The distal end of the hollowtube 304 extends beyond the distal end of the second tube 202.

In the preferred embodiment, the blade 306 is made of stainless steeland affixed to the end of the hollow tube 304 by screws 308a, 308b whichpass through the blade 306 and into the tube 304. The blade 306 is,thus, removeable or replaceable. The screws 308a, 308b are preferablyflush with the surface of the blade 306. As shown in FIG. 4, the blade306 is curved. This allows the blade to "scoop" away the resectedtissue.

The hollow tube 304 also has extending therefrom at the distal endthereof, but before the cutting blade 306 a first projection 312 (FIG.4) which projects outwardly or radially away from the hollow tube 304and beyond the helical threads 305. The first projection plays animportant role in movement of the laser 400, as will be discussed later.

The opening 302 extends completely longitudinally through the hollowtube 304, and the longitudinal axis of the opening 302 is concentricwith the longitudinal axes of the first and second tubes 101, 202. Theopening 302 through the hollow tube 304 is designed to receive and housethe telescope 500 therein. The telescope 500 is of conventionalconstruction and includes a connection 502 for a light source and has aneyepiece 504 for use in reviewing the area of the prostate gland orbladder to be cut with the resectoscope 10. The use of such a telescopein such a manner is known in the art.

The drive mechanism 600 is preferably a pneumatic-type system 602 suchas that known in the medical art to run drills, e.g. a dentist'spneumatic drill. While shown in simplified form in FIGS. 2A and 3, thespecific construction and connection of such a drive system 602 to therod 304 in order to rotate the rod are well known to those skilled inthe art and are not presented in detail herein. However, as shown inFIGS. 2A and 3, a pneumatic drive 602 rotates a threaded shaft 604 whichin turn causes gear wheel 606 to rotate. The rod 304 is secured to thegear wheel 606 by a screw 607. A seal 609 prevents irrigation fluid fromentering into the drive housing 610. It is preferred that the speed ofthe rotation of the rod 304 be controllable by means of a foot pedal(not shown) which regulates the flow of high pressure air to the drivesystem 602. It should be understood that while a pneumatic drive ispreferred, other means of rotating the hollow tube, such as by differenttypes of electrical motors might also be used. The drive mechanism isnot intended to be limited to any specific form. A pnuematic drivemechanism is preferred because it is more easily cleaned and sterilized.

To more accurately control the rotation of the rod 304 and the cuttingof the blade 306 attached thereto, an additional hand-operable pawl andratchet-type drive mechanism 608 (FIG. 3) may be provided in order torotate the rod 304 independent of the rotation imparted by the pneumaticdrive 602. A pawl and ratchet drive 608 is not considered to be uniqueand construction of such a means for continuously, yet manually,rotating the rod 304 is well known to those skilled in the art and isnot discussed at length herein. An example of such a type of mechanismis the type of mechanism used in a manual rapid photographic filmadvance system.

As shown in FIG. 2A, passing through the first tube 101 at the rearwardor proximal portion of the tube 101 is the laser member 400. The lasermember 400 includes an inlet tube 404 which passes through the firsttube 101 and communicates with the third sheath or tube 402. The thirdtube passes longitudinally through the space 112 between the first andsecond tubes 101, 202 toward the end of the hollow tube 304 having thecutting blade 306 thereon. The third tube 402 is preferably made ofresilient stainless steel and is affixed, for example by a weld, at itsproximal end to the second tube 202. In this manner, the rearward orproximal end of the third tube 402 is stationarily positioned inrelation to the second tube 202. The opposite or distal end of the thirdtube 402, the end adjacent the blade 306, however, is free to movethrough a limited radial arc. The distal end of the third tube 402extends in front of the first projection 312 on the hollow tube so thatthe first projection 312 abuts the third tube 402 as the hollow tube 304rotates and thereby forces the third tube 402 ahead to move in thedirection of rotation of the rod 304.

To prevent the third tube 402 from wrapping around the second tube 202,a special configuration is provided on the second tube 202 as shown inFIG. 4. The second tube 202 has at least near the distal end thereof asecond projection or cam 208 which gradually projects outward radiallyfrom the circumference of the second tube 202 a distance greater thanthe distance which the first projection 312 extends beyond the generalcircumference of the second tube 202. When the third tube 402 (whichusually lies adjacent to the second tube 202) is engaged by the firstprojection 312 as the hollow tube 304 rotates, the third tube 402 movesaround the second tube 202 under the force exerted by the firstprojection 312 and advances upward along the cam 208 as shown by thephantom lines in FIG. 4. When the third tube 402 is atop the secondprojection 208 at the position farthest away from the generalcircumference of the second tube, the third tube is spaced so farradially from the second tube that the first projection 312 passesunderneath the third tube 402 and no longer causes the third tube tomove radially about the second tube 202.

A spring 406 is attached between the third tube 402 and second tube 202near the free end of the third tube so that the third tube is urged backtoward the second tube after it reaches the top of the second projection208 and clears the head of the first projection 312. The purpose of thespring 406 is to return the third tube 402 to its initial position asquickly as possible so that the third tube is in position to be engagedby the first projection 312 when it begins the next cycle of rotation.Although a coiled spring 406 is shown, any suitable biasing device maybe used. In this manner, as the hollow tube 304 passes through eachcomplete rotation, the first projection 312 abuts the third tube andurges it forward in front of the blade 306 until the third tube rides tothe top of the cam 208. When the third tube 402 clears the firstprojection 312, it is pulled back to its position adjacent the secondtube 202 under the urging of the biasing spring 406.

The purpose of the third tube 402 is to provide a sheath for the opticfiber filament 408 to pass therethrough. The filament 408 is insertedthrough a resilient gasket-type fitting 410 (FIG. 1) (which fits tightlyaround the filament 408), through the inlet tube 404 and onward towardthe open distal end of the third tube 402. As the third tube moves alongthe cam 208, the laser light beam projected from the end of the opticfiber filament 408 is directed outward from the third tube 402 in frontof and parallel to the cutting edge 310 of the blade 306. The opticfilament, of course, reciprocates back and forth with the motion of thethird tube.

The hood 106 of the first tube 101 is positioned in front of the opticfiber filament 408 in such a manner that the laser beam from thefilament does no forward laser cutting of tissue. The hood 106 stops orabsorbs the forward laser light from the optic fiber filament. The onlycutting by the laser light is along the line parallel to the cuttingedge 310 of the blade 306.

The proximal end of the optic filament 408 is connected to a lasergenerator 412 which is provided with a foot control. As an example, aKTP/532 Laser by Laserscope of Santa Clara, Calif. is a suitable type ofoptic fiber laser system. The optic fiber filament 408 is typically a400 u optic laser cable.

The laser, when energized, assists in cutting and also assists incoagulating the tissue to stop or mininize bleeding. Preferably, theoptic fiber filament 408 is attached to a laser generator atapproximately 532 nm with a power of 5-15 watts pulsed at 0.10-0.5seconds. A foot pedal is used to energize the laser. At times during theresection procedure, the distance of the optic fiber filament 408 to thetarget tissue may need to be adjusted in order to control cutting orcoagulation (as known in the art.) The distance is regulated simply bymanually pushing or pulling the filament 408 through the gasket 410. Thegasket 410 holds the filament sufficiently tightly so that oncemanipulation of the filament is complete, the filaments stays tightly atthe selected location within the third tube 402.

In order to perform the resection of the prostate, the resectoscope 10is inserted through the urethra toward the prostate and the area whereresection is desired. Irrigation fluid 114 is provided through theconduit 102 and valve 104 to the inside of the first tube 101. The fluidflows within the space 112 between the first and second tubes toward thehood 106 portion of the first tube. The irrigation fluid serves toirrigate and clear the area being resected, and in order to keep thearea clear, the fluid is removed from the cutting area through thesecond tube 202 by being drawn through the conduit 203 through valve 204which is connected to the vacuum source. While the vacuum tends towithdraw the irrigation fluid and resected chips, the rotation of thehollow tube 304 with the threads 305 therearound also causes fluid flowin the direction of the outlet conduit 203.

Upon engaging the drive mechanism 600, the hollow tube 304 rotates theblade 306 at the end thereof. The first projection 312 (as discussedpreviously) contacts the third tube 402 and begins to advance the thirdtube and the optic filament 408 within the third tube. The laser isactivated in the required manner, and the laser light beam projectingfrom the optic filament within the third tube is directed in a pathparallel to and in front of the cutting edge 310 of the blade 306 toprovide a cutting and coagulating function.

In order to view the process of the cutting, the operator views thecutting location through the telescope 500 which is inserted through theopening 302 in the rod 304. Preferably, the telescope is a 30 degreetelescope and has a light source connected thereto at connection 502. Byproviding this telescopic vision, the entire procedure can be donevisually.

As has been explained previously, rotation of the rod 304 is producedand controlled preferably by a pneumatic drive system 602, and movementof the rod 304 causes movement of the third tube 402 containing thefilament 408 in advance thereof. If more precise cutting is necessary,movement of the hollow tube 304 can be controlled manually by the manualsystem 608. In addition to manually controlling the motion of the hollowtube 304 and the laser light in front of the blade, this manual controlcan also be used to direct the optic fiber filament toward anyparticular area which may be bleeding and needs to be coagulated sincethe optic fiber moves along with the tube 402 when it is contacted bythe projection 312 on the hollow tube 304.

In a further embodiment of the invention, the laser resectoscope 10 ofthe invention is operated in conjunction with a computer 800 in order tocontrol cutting by the resectoscope 10 and thereby prevent theunintentional breaching of the prostate capsule or the peripheral zoneduring prostate surgery. As shown in FIG. 6 the prostate 700 comprises acentral zone 702 surrounded by a peripheral zone 704 and capsule 706surrounding the urethra 708. Only the central zone 702 is removed duringtransurethral prostate resectioning, and in particular, the capsule 706and peripheral zone 704 are not to be breached during the surgery.

To have a better idea of the size of the prostate being resectioned andthe location of the boundaries of the central zone 702 prior tocommencing the prostate surgery, by using known ultrasound technology,ultrasound probes can be used to measure and diagram, with theassistance of a computer 800 connected to the probe(s), the shape of theprostate 700. For example, by using either a rectal probe or anabdominal probe (such as produced by Bruel & Kjaer of Denmark), a threedimensional scan is made of the prostate by feeding the ultrasound scansinto a computer 800 where an image is prepared showing the central zoneof the prostate in addition to the capsule and the peritheral zone.

The image boundaries of these specific locations within the prostate areretained in the computer so that the computer can be instructed whichareas of tissue are to be removed and therefore, which regions of theprostate the laser cannot be allowed to penetrate.

The use of ultrasound probes is known in the art to permit computerimaging of the prostate. However, it is not known in the art to connectthe computer 800 (wherein the image is stored) to a resectoscope 10 inorder to control the cutting operation of the resectoscope, and inparticular such a connection is not known with a resectoscope utilizinga laser light for cutting. If, during the resecting process the laserlight begins to come within an unacceptably close range of the edge ofthe capsule 706 or the peripheral zone 704, so that there is apossibility of breaching the capsule or peripheral zone, the computer800 in conjunction with ultrasound probing detects the nearness of thelaser or cutting blade to the capsule or peripheral zone and willautomatically direct the shut off of the laser generator. In this way,inadvertant resection of the capsule or peripheral zone is avoided.

The ultrasound probing need not be continuous throughout the entireoperation; however, during at least that part of the resection where thesurgeon feels the resectoscope is getting close to the capsule or theperitheral zone, the ultrasound can again be applied to the prostatearea to follow the location of the resectoscope 10. By comparing thelocation of the resectoscope 10 to the previously generated image of theprostate 700, the computer 800 can be used to detect when the laserresectoscope scope is getting too close to an area which should not bepenetrated and turn off the laser. The computer 800 is used to onlycontrol the operation of the laser. Neither the light source nor theultrasound activity is affected by the computer.

It is recognized that as skills in the use of computers and ultrasoundincrease, additional methods of computing or determining the location ofthe resectoscope within the central zone may be developed. These futureadvances in technology are, however, considered to be within the realmof the computer-assisted technique disclosed herein.

Without further elaboration, the foregoing will so fully illustrate myinvention that others may, by applying current or future knowledge,readily adopt the same for use under various conditions of service.

What is claimed as the invention is:
 1. A surgical apparatus forcoagulating tissue of the prostate of a living being, said apparatuscomprising:elongated introduction means configured for introductionthrough the urethra into said being, said introduction means beingpositionable adjacent said prostate within said being; laser meansassociated within said introduction means and configured forintroduction by said introduction means to a location within saidurethra adjacent said prostate, said laser means being controllable forproducing and directing a laser beam through said urethra into saidprostate tissue adjacent said introduction means for coagulating saidprostate tissue; ultrasonic imaging means coupled to said laser meansfor introduction into the body of said being adjacent said prostate toprovide an image of at least a portion of said prostate tissue as saidlaser means is operated to enable said laser means to be controlled tocoagulate said adjacent prostate tissue while precluding injury to otheradjacent tissue; and tissue removal means for removing at least aportion of said coagulated prostate tissue from said prostate.
 2. Asurgical apparatus as claimed in claim 1, wherein:said introductionmeans has a distal end portion and said distal end portion ispositionable adjacent said prostate tissue; said laser beam is providedat said distal end of said introduction means.
 3. The apparatus of claim1 wherein said tissue removal means is arranged to operate substantiallycontemporaneously with the operation of said laser.
 4. The apparatus ofclaim 3 wherein said tissue removal means comprises means for carryingsaid removed coagulated prostate tissue out of the body of said being.5. The apparatus of claim 4 wherein said tissue removal meansadditionally comprises cutting means.
 6. The apparatus of claim 5wherein said cutting means is arranged to be rotated about an axis. 7.The apparatus of claim 4 wherein said means for carrying said removedcoagulated tissue comprises suction means.
 8. The apparatus of claim 1wherein said tissue removal means comprises cutting means.
 9. Theapparatus of claim 8 wherein said cutting means is arranged to berotated about an axis.
 10. A method of coagulating tissue of theprostate of a living being, said method comprising the stepsof:introducing elongated means through the urethra into the body of saidbeing to a position adjacent said prostate, said elongated means havingcontrollable laser means therein for providing a laser beam; operatingsaid laser means in order to produce a laser beam and directing saidlaser beam through said urethra into said prostate tissue adjacent saidelongated means in order to coagulate said prostate tissue; utilizingultrasonic imaging means coupled to said laser means and inserted intothe body of said being to a location adjacent said prostate to providean image of at least a portion of said prostate tissue as said lasermeans is operated to enable said laser means to be controlled tocoagulate said adjacent prostate tissue while precluding injury to otheradjacent tissue.
 11. The method as claimed in claim 10 wherein:saidelongated means has a distal end portion, and wherein said methodadditionally comprises introducing said distal end portion to a positionadjacent said prostate tissue; and wherein said laser beam emanates fromsaid distal end portion of said elongated means.
 12. The method of claim10 additionally comprising the step of removing at least a portion ofsaid coagulated prostate tissue from the body of said being.
 13. Themethod of claim 12 wherein said coagulated prostate tissue is removedfrom the body of said being substantially contemporaneously with theoperation of said laser means.
 14. The method of claim 12 additionallycomprising the step of carrying said coagulated prostate tissue out ofthe body of said being.
 15. The method of claim 12 wherein saidcoagulated prostate tissue is cut from said prostate.
 16. The method ofclaim 15 wherein said cutting is accomplished by a rotatable cutter. 17.The method of claim 15 wherein coagulated tissue is removed from thebody of said being by suction.
 18. The method of claim 12 whereincoagulated tissue is removed from the body of said being by suction.